CVE-2016-4491 in libiberty
Summary
by MITRE
The d_print_comp function in cp-demangle.c in libiberty allows remote attackers to cause a denial of service (segmentation fault and crash) via a crafted binary, which triggers infinite recursion and a buffer overflow, related to a node having "itself as ancestor more than once."
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Analysis
by VulDB Data Team • 08/17/2020
The vulnerability identified as CVE-2016-4491 represents a critical flaw in the GNU binutils library component known as libiberty, specifically within the cp-demangle.c file. This issue affects the demangling functionality that processes C++ mangled symbol names, which are essential for debugging and analyzing compiled binary code. The vulnerability manifests when the d_print_comp function encounters a specially crafted binary that contains malformed symbol references, leading to system instability and potential service disruption.
The technical root cause of this vulnerability stems from inadequate validation of recursive symbol references during the demangling process. When the d_print_comp function processes a node structure that contains self-referencing elements or circular dependencies in its ancestry chain, it fails to properly detect and terminate these recursive patterns. This flaw creates an infinite recursion scenario where the function calls itself repeatedly without proper termination conditions, ultimately exhausting system stack resources and causing segmentation faults. The vulnerability specifically targets nodes that have "itself as ancestor more than once," indicating a recursive data structure pattern that the demangler cannot properly handle.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be exploited by remote attackers to disrupt services that rely on symbol demangling functionality. Systems that process or analyze binary files, particularly those involving debugging tools, reverse engineering frameworks, or software development environments, become vulnerable to this attack vector. The crash occurs during normal operation when legitimate binary analysis tools attempt to process the malicious input, making this a particularly dangerous vulnerability for development environments and security analysis platforms. The buffer overflow component adds additional risk as it can potentially be leveraged for more sophisticated attacks if combined with other vulnerabilities or if the system has additional memory corruption weaknesses.
Mitigation strategies for CVE-2016-4491 should focus on immediate patching of affected libiberty versions, as the vulnerability exists in the core demangling functionality that is widely used across various GNU tools and development environments. Organizations should prioritize updating their binutils installations and any software that depends on libiberty for symbol processing. Implementing input validation measures and limiting the scope of binary analysis to trusted sources can provide additional defense layers. From a cybersecurity perspective, this vulnerability aligns with CWE-674, which addresses Uncontrolled Recursion, and can be mapped to ATT&CK technique T1059.001 for Abuse of Command and Scripting Interpreters. The vulnerability demonstrates the importance of proper recursion termination in parsing algorithms and highlights the need for robust input sanitization in security-critical components that handle user-supplied binary data.